[PATCH v2 3/3] iommu/amd: Add support for IOMMU XT mode

From: Suravee Suthikulpanit
Date: Wed Jun 27 2018 - 11:32:33 EST


The AMD IOMMU XT mode enables interrupt remapping with 32-bit destination
APIC ID, which is required for x2APIC. The feature is available when
the XTSup bit is set in the IOMMU Extended Feature register
and/or the IVHD Type 10h IOMMU Feature Reporting field.

For more information, please see section "IOMMU x2APIC Support" of
the AMD I/O Virtualization Technology (IOMMU) Specification.

Cc: Joerg Roedel <jroedel@xxxxxxx>
Signed-off-by: Suravee Suthikulpanit <suravee.suthikulpanit@xxxxxxx>
---
drivers/iommu/amd_iommu.c | 21 ++++++++++++++++-----
drivers/iommu/amd_iommu_init.c | 25 +++++++++++++++++++++++--
drivers/iommu/amd_iommu_types.h | 17 +++++++++++------
3 files changed, 50 insertions(+), 13 deletions(-)

diff --git a/drivers/iommu/amd_iommu.c b/drivers/iommu/amd_iommu.c
index 92241ff..6b2c9e5 100644
--- a/drivers/iommu/amd_iommu.c
+++ b/drivers/iommu/amd_iommu.c
@@ -3843,7 +3843,8 @@ static void irte_ga_prepare(void *entry,
irte->lo.fields_remap.int_type = delivery_mode;
irte->lo.fields_remap.dm = dest_mode;
irte->hi.fields.vector = vector;
- irte->lo.fields_remap.destination = dest_apicid;
+ irte->lo.fields_remap.destination = APICID_TO_IRTE_DEST_LO(dest_apicid);
+ irte->hi.fields.destination = APICID_TO_IRTE_DEST_HI(dest_apicid);
irte->lo.fields_remap.valid = 1;
}

@@ -3896,7 +3897,10 @@ static void irte_ga_set_affinity(void *entry, u16 devid, u16 index,

if (!irte->lo.fields_remap.guest_mode) {
irte->hi.fields.vector = vector;
- irte->lo.fields_remap.destination = dest_apicid;
+ irte->lo.fields_remap.destination =
+ APICID_TO_IRTE_DEST_LO(dest_apicid);
+ irte->hi.fields.destination =
+ APICID_TO_IRTE_DEST_HI(dest_apicid);
modify_irte_ga(devid, index, irte, NULL);
}
}
@@ -4313,7 +4317,10 @@ static int amd_ir_set_vcpu_affinity(struct irq_data *data, void *vcpu_info)
irte->lo.val = 0;
irte->hi.fields.vector = cfg->vector;
irte->lo.fields_remap.guest_mode = 0;
- irte->lo.fields_remap.destination = cfg->dest_apicid;
+ irte->lo.fields_remap.destination =
+ APICID_TO_IRTE_DEST_LO(cfg->dest_apicid);
+ irte->hi.fields.destination =
+ APICID_TO_IRTE_DEST_HI(cfg->dest_apicid);
irte->lo.fields_remap.int_type = apic->irq_delivery_mode;
irte->lo.fields_remap.dm = apic->irq_dest_mode;

@@ -4430,8 +4437,12 @@ int amd_iommu_update_ga(int cpu, bool is_run, void *data)
raw_spin_lock_irqsave(&table->lock, flags);

if (ref->lo.fields_vapic.guest_mode) {
- if (cpu >= 0)
- ref->lo.fields_vapic.destination = cpu;
+ if (cpu >= 0) {
+ ref->lo.fields_vapic.destination =
+ APICID_TO_IRTE_DEST_LO(cpu);
+ ref->hi.fields.destination =
+ APICID_TO_IRTE_DEST_HI(cpu);
+ }
ref->lo.fields_vapic.is_run = is_run;
barrier();
}
diff --git a/drivers/iommu/amd_iommu_init.c b/drivers/iommu/amd_iommu_init.c
index 7d494f2..f6dd63f 100644
--- a/drivers/iommu/amd_iommu_init.c
+++ b/drivers/iommu/amd_iommu_init.c
@@ -153,6 +153,7 @@ bool amd_iommu_dump;
bool amd_iommu_irq_remap __read_mostly;

int amd_iommu_guest_ir = AMD_IOMMU_GUEST_IR_VAPIC;
+static int amd_iommu_xt_mode = IRQ_REMAP_X2APIC_MODE;

static bool amd_iommu_detected;
static bool __initdata amd_iommu_disabled;
@@ -827,6 +828,19 @@ static int iommu_init_ga(struct amd_iommu *iommu)
return ret;
}

+static void iommu_enable_xt(struct amd_iommu *iommu)
+{
+#ifdef CONFIG_IRQ_REMAP
+ /*
+ * XT mode (32-bit APIC destination ID) requires
+ * GA mode (128-bit IRTE support) as a prerequisite.
+ */
+ if (AMD_IOMMU_GUEST_IR_GA(amd_iommu_guest_ir) &&
+ amd_iommu_xt_mode == IRQ_REMAP_X2APIC_MODE)
+ iommu_feature_enable(iommu, CONTROL_XT_EN);
+#endif /* CONFIG_IRQ_REMAP */
+}
+
static void iommu_enable_gt(struct amd_iommu *iommu)
{
if (!iommu_feature(iommu, FEATURE_GT))
@@ -1507,6 +1521,8 @@ static int __init init_iommu_one(struct amd_iommu *iommu, struct ivhd_header *h)
iommu->mmio_phys_end = MMIO_CNTR_CONF_OFFSET;
if (((h->efr_attr & (0x1 << IOMMU_FEAT_GASUP_SHIFT)) == 0))
amd_iommu_guest_ir = AMD_IOMMU_GUEST_IR_LEGACY;
+ if (((h->efr_attr & (0x1 << IOMMU_FEAT_XTSUP_SHIFT)) == 0))
+ amd_iommu_xt_mode = IRQ_REMAP_XAPIC_MODE;
break;
case 0x11:
case 0x40:
@@ -1516,6 +1532,8 @@ static int __init init_iommu_one(struct amd_iommu *iommu, struct ivhd_header *h)
iommu->mmio_phys_end = MMIO_CNTR_CONF_OFFSET;
if (((h->efr_reg & (0x1 << IOMMU_EFR_GASUP_SHIFT)) == 0))
amd_iommu_guest_ir = AMD_IOMMU_GUEST_IR_LEGACY;
+ if (((h->efr_reg & (0x1 << IOMMU_EFR_XTSUP_SHIFT)) == 0))
+ amd_iommu_xt_mode = IRQ_REMAP_XAPIC_MODE;
break;
default:
return -EINVAL;
@@ -1832,6 +1850,8 @@ static void print_iommu_info(void)
pr_info("AMD-Vi: Interrupt remapping enabled\n");
if (AMD_IOMMU_GUEST_IR_VAPIC(amd_iommu_guest_ir))
pr_info("AMD-Vi: virtual APIC enabled\n");
+ if (amd_iommu_xt_mode == IRQ_REMAP_X2APIC_MODE)
+ pr_info("AMD-Vi: X2APIC enabled\n");
}
}

@@ -2168,6 +2188,7 @@ static void early_enable_iommu(struct amd_iommu *iommu)
iommu_enable_event_buffer(iommu);
iommu_set_exclusion_range(iommu);
iommu_enable_ga(iommu);
+ iommu_enable_xt(iommu);
iommu_enable(iommu);
iommu_flush_all_caches(iommu);
}
@@ -2212,6 +2233,7 @@ static void early_enable_iommus(void)
iommu_enable_command_buffer(iommu);
iommu_enable_event_buffer(iommu);
iommu_enable_ga(iommu);
+ iommu_enable_xt(iommu);
iommu_set_device_table(iommu);
iommu_flush_all_caches(iommu);
}
@@ -2691,8 +2713,7 @@ int __init amd_iommu_enable(void)
return ret;

irq_remapping_enabled = 1;
-
- return 0;
+ return amd_iommu_xt_mode;
}

void amd_iommu_disable(void)
diff --git a/drivers/iommu/amd_iommu_types.h b/drivers/iommu/amd_iommu_types.h
index 986cbe0..aa892fd 100644
--- a/drivers/iommu/amd_iommu_types.h
+++ b/drivers/iommu/amd_iommu_types.h
@@ -161,6 +161,7 @@
#define CONTROL_GAM_EN 0x19ULL
#define CONTROL_GALOG_EN 0x1CULL
#define CONTROL_GAINT_EN 0x1DULL
+#define CONTROL_XT_EN 0x32ULL

#define CTRL_INV_TO_MASK (7 << CONTROL_INV_TIMEOUT)
#define CTRL_INV_TO_NONE 0
@@ -378,9 +379,11 @@
#define IOMMU_CAP_EFR 27

/* IOMMU Feature Reporting Field (for IVHD type 10h */
+#define IOMMU_FEAT_XTSUP_SHIFT 0
#define IOMMU_FEAT_GASUP_SHIFT 6

/* IOMMU Extended Feature Register (EFR) */
+#define IOMMU_EFR_XTSUP_SHIFT 2
#define IOMMU_EFR_GASUP_SHIFT 7

#define MAX_DOMAIN_ID 65536
@@ -437,7 +440,6 @@ extern struct kmem_cache *amd_iommu_irq_cache;
#define APERTURE_RANGE_INDEX(a) ((a) >> APERTURE_RANGE_SHIFT)
#define APERTURE_PAGE_INDEX(a) (((a) >> 21) & 0x3fULL)

-
/*
* This struct is used to pass information about
* incoming PPR faults around.
@@ -810,6 +812,9 @@ union irte {
} fields;
};

+#define APICID_TO_IRTE_DEST_LO(x) (x & 0xffffff)
+#define APICID_TO_IRTE_DEST_HI(x) ((x >> 24) & 0xff)
+
union irte_ga_lo {
u64 val;

@@ -823,8 +828,8 @@ union irte_ga_lo {
dm : 1,
/* ------ */
guest_mode : 1,
- destination : 8,
- rsvd : 48;
+ destination : 24,
+ ga_tag : 32;
} fields_remap;

/* For guest vAPIC */
@@ -837,8 +842,7 @@ union irte_ga_lo {
is_run : 1,
/* ------ */
guest_mode : 1,
- destination : 8,
- rsvd2 : 16,
+ destination : 24,
ga_tag : 32;
} fields_vapic;
};
@@ -849,7 +853,8 @@ union irte_ga_hi {
u64 vector : 8,
rsvd_1 : 4,
ga_root_ptr : 40,
- rsvd_2 : 12;
+ rsvd_2 : 4,
+ destination : 8;
} fields;
};

--
2.7.4